Glossary of Geologic and Architectural Terms
Antefix—an ornament along the edge of a roof, often shaped like a shell or shield
Baluster—a post or support for a handrail
Balustrade—a rail and row of supporting posts, especially along a stair or porch
Bronze—a metal alloy of copper and tin; although brown when fresh, it weathers to a more commonly seen green color
Calcite—a mineral composed of calcium carbonate: CaCO₃
Column Capital—The top portion of a column. There are three main types; from least ornate to most ornate, they are Doric, Ionic, and Corinthian
Diabase—a dark-gray to black, fine-textured igneous rock, composed of the minerals feldspar and pyroxene
Feldspar—a common mineral composed of silica (Si), aluminum (Al), and calcium (Ca), potassium (K), or sodium (Na): CaAl₂Si₂O₈, KAlSi₃O₈, NaAlSi₃O₈
Fossil—remains or trace of a plant or animal preserved in a rock from some past, prehistoric time
Granite—a light or speckled, coarse-grained igneous rock composed of quartz, feldspar, and mica
Guttae—small, drop-like rounded ornaments under a roof overhang
Gypsum—a mineral composed of hydrated calcium sulfate: CaSO₄·2H₂O
Igneous—formed from melted or partially molten rock
Inclusion—a mineral phase that is distinct (in composition or appearance) from the main mineral components of a rock
Limestone—a sedimentary rock, chiefly composed of calcium carbonate; formed from the shells of marine animals
Marble—a metamorphic rock, chiefly composed of calcium carbonate
Metamorphic—changed; usually by heat or pressure to a different form but the same composition
Mica—a silicate mineral that forms sheets or layers and contains aluminum, hydroxyl, and alkali ions: K₂Al₄Si₆Al₂O₂₀(OH,F)₄, K₂(Mg,Fe)₆Si₆Al₂O₂₀(OH,F)₄
Mineral—a naturally occurring inorganic substance with an ordered structure; rocks are made of one or more minerals
Portico—a porch, with a roof supported by columns
Pyrite—a mineral (“fool’s gold”) composed of iron sulfide: FeS₂
Pyroxene—a silicate mineral containing two metal oxides: CaMgSi₂O₆, CaFeSi₂O₆, (Mg,Fe)SiO₃
Quartz—a mineral composed of silicon dioxide, or silica: SiO₂
Sandstone—a sedimentary rock composed chiefly of quartz grains
Sedimentary—formed from particles that were transported by water or wind and deposited in layers
Volute—a scroll-like ornament on an Ionic column capital